System for automatic color balance correction
AssigneeRobert Bosch GmbH
InventorDieter Poetsch
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Abstract
Color balance of a color television picture is corrected during those periods when the luminosity falls within prespecified limits and when simultaneously the chroma-saturation is below a prespecified level. A switch operates to change the time constant of an integrator for derivation of a control signal indicative of when the simultaneous conditions are met. One time constant is used when the simultaneous conditions begin and another when they end, thereby allowing better correction of color stains which do not extend uniformly over the entire picture.
Claims4
In a system for automatic correction of the color balance of signals that control color and luminosity of a color television picture, in which system, when a prespecified luminosity gradation in the color television picture is detected and when at the same time the chroma-saturation is below a prespecified chroma-saturation threshold, a chromaticity of the television picture prevailing at this moment is stored, so as to derive, as a function of the stored chromaticity, control signals for regulating a color-correction device in such a way that a chromatic aberration in the color balance of the signals that control color and luminosity of a color television picture is reduced, the improvement comprising:
- integrator means operative at one time constant when said prespecified luminosity gradation in the color television picture is detected to up-integrate color difference signals, and operative at a different time constant when any luminosity other than said prespecified luminosity gradation is detected to down integrate in response to a different input signal.
Dependencies are inferred from the claim text.